Platform (geology)


Platform (geology)
Geologic provinces of the world (USGS)
  Shield
  Platform
  Orogen
  Basin
  Extended crust
Oceanic crust:
  0–20 Ma
  20–65 Ma
  >65 Ma

In geology, a platform is a continental area covered by relatively flat or gently tilted, mainly sedimentary strata, which overlie a basement of consolidated igneous or metamorphic rocks of an earlier deformation. Platforms, shields and the basement rocks together constitute cratons.

It is also common practice to use the term platform as a general term for a sequence of shallow water carbonate platforms. Carbonate platforms can develop in almost any tectonic setting, but they are particularly common along passive margins. Many oilfields produce from sediments deposited along carbonate platforms.

Details of emersive cycles "shallowing upward sequences" in two sections distant of 230km. Note on top the tempestite and tsunami(?) deposits, with displaced, floated foraminifera.

Various types of carbonate platforms are recognised, including (but are not restricted to) rimmed shelf, ramp, epiric platforms, isolated platforms and drowned platforms. An example of carbonate "bahamian type" platform, in a paleotectonic context of continental rifting during the Lias is the high Atlas of Morocco (Septfontaine, 1985). The coastal and lagoonal to supratidal "chotts" deposits of southern Tunisia (Zarzis area) is also a good recent equivalent model (Davaud & Septfontaine, 1995).

High Atlas liassic carbonate platform of Morocco and first order metric (autocyclic)regressive cycles.
Virtual "shallowing upward sequence" observed all along the southern margin of the Tethys during liassic times (over 10.000km).

See also

References

  • Davaud, E. & Septfontaine, M. (1995): Post-mortem onshore transportation of epiphytic foranifera: recent example from the Tunisian coastline.- Jour. Sediment. Research, 65/1A, 136-142. See www.palgeo.ch/publications.
  • Parker, Sybil P. (Ed.). 1997. McGraw-Hill Dictionary of Geology and Mineralogy. New York: McGraw-Hill.
  • Septfontaine, M. (1985): Depositional environments and associated foraminifera (lituolids) in the middle liassic carbonate platform of Morocco.- Rev. de Micropal,(Paris), 28/4, 265-289. See also www.palgeo.ch/publications.
  • Tucker, Maurice E. 1990. Carbonate Sedimentology. Oxford: Blackwell Science.

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Platform — The word platform is used in several different contexts, usually referring to some kind of standing surface used to support things, give them stability, or visibility:* Railway platform, an area at a train station to alight from/embark on trains… …   Wikipedia

  • Geology of Colombia — refers to the geological composition of the Republic of Colombia that determines its geography. The territory of Colombia covers vast areas within the South American plate, where most of the emerged land is, the Caribbean plate and the Nazca… …   Wikipedia

  • Geology of the Death Valley area — The exposed geology of the Death Valley area presents a diverse and complex story that includes at least 23 formations of sedimentary units, two major gaps in the geologic record called unconformities, and at least one distinct set of related… …   Wikipedia

  • Geology of Australia — Australia is a continent situated on the Indo Australian Plate.The geology of Australia includes virtually all known rock types and from all geological time periods spanning over 3.8 billion years of the Earth s history. ComponentsAustralia s… …   Wikipedia

  • Geology of North America — The geology of North America, like most topics of scientific study, is undergoing progressive investigation by numerous public and private sector earth scientists, academicians, and students. In that regard, the detailed picture is subject to… …   Wikipedia

  • Geology of the Iberian Peninsula — The geology of the Iberian Peninsula consists of the study of the rock formations on the Iberian Peninsula, which includes Spain, Portugal, Andorra, and Gibraltar. The peninsula contains rocks from every age from Ediacaran to Recent, and almost… …   Wikipedia

  • Geology of the North Sea — Contents 1 Tectonic structure 2 Precambrian 3 Finnmarkian, Athollian, Caledonian Orogenies …   Wikipedia

  • Geology of the Grand Canyon area — The geology of the Grand Canyon area exposes one of the most complete sequences of rock anywhere, representing a period of nearly 2 billion years of the Earth s history in that part of North America. The major sedimentary rock layers exposed in… …   Wikipedia

  • Geology of the Pacific Northwest — The geology of the Pacific Northwest refers to the study of the composition (including rock, minerals, and soils), structure, physical properties and the processes that shape the Pacific Northwest region of the United States and Canada. The… …   Wikipedia

  • Geology of Jersey — The geology of Jersey is characterised by the Late Proterozoic Brioverian volcanics, the Cadomian Orogeny, and only small signs of later deposits from the Cambrian and Quaternary periods. The kind of rocks go from conglomerate to shale, volcanic …   Wikipedia